Kalahari Desert
The Kalahari Desert (in Afrikaans Kalahari-woestyn) is a large semi-arid sandy savannah in southern Africa extending 900,000 square kilometres (350,000 sq mi), covering much of Botswana and parts of Namibia and South Africa. A semi-desert, with huge tracts of excellent grazing after good rains, the Kalahari supports more animals and plants than a true desert, such as the Namib Desert to the west. There are small amounts of rainfall and the summer temperature is very high. The driest areas usually receive 110–200 millimetres (4.3–7.9 in) of rain per year., and the wettest just a little over 500 millimetres (20 in). The surrounding Kalahari Basin covers over 2,500,000 square kilometres (970,000 sq mi) extending farther into Botswana, Namibia and South Africa, and encroaching into parts of Angola, Zambia and Zimbabwe. The Kalahari is home to many migratory birds and animals. Previously havens for wild animals from elephants to giraffes, and for predators such as lions and cheetahs, the riverbeds are now mostly grazing spots, though leopards and cheetahs can still be found. The area is now heavily grazed and cattle fences restrict the movement of wildlife. Among deserts of the southern hemisphere the Kalahari most closely resembles some Australian deserts in its latitude and its mode of formation. Short Description Derived from the Tswana word Kgala, meaning "the great thirst", or Khalagari, Kgalagadi or Kalagare, meaning "a waterless place", the Kalahari has vast areas covered by red sand without any permanent surface water. Drainage is by dry valleys, seasonally inundated pans, and the large salt pans of the Makgadikgadi Pan in Botswana and Etosha Pan in Namibia. The only permanent river, the Okavango, flows into a delta in the northwest, forming marshes that are rich in wildlife. Ancient dry riverbeds—called omuramba—traverse the Central Northern reaches of the Kalahari and provide standing pools of water during the rainy season. Flora Despite its aridity, the Kalahari supports a variety of flora. The native flora includes acacia trees and many other herbs and grasses. The Kiwano fruit, also known as the Horned melon, melano, African horned cucumber, jelly melon, or hedged gourd, is endemic to a region in the Kalahari Desert (*specific region unknown). Even where the Kalahari "desert" is dry enough to qualify as a desert in the sense of having low precipitation, it is not strictly speaking a desert because it has too dense a ground cover, often close to 100%. The main region that lacks ground cover is in the southwest Kalahari (southeast of Namibia and northwest of South Africa around the Kgalagadi Transfrontier Park). In an area of about 600,000 km² in the south and west of the Kalahari the vegetation is mainly xeric savanna. This area is the ecoregion identified by World Wide Fund for Nature as Kalahari xeric savanna AT1309. Typical savanna grasses include (Schmidtias, Stipagrostis, Aristida, and Eragrostis interspersed with trees such as camelthorn (Acacia erioloba), grey camelthorn (Acacia haematoxylon), shepherd’s tree (Boscia albitrunca), blackthorn (Acacia mellifera), and silver cluster-leaf (Terminalia sericea). In certain areas where the climate is drier it becomes a true semi-desert with ground not entirely covered by vegetation, an "open" vegetation as opposed to "closed" vegetation. Examples include the north of the Siyanda District, itself in the north of South Africa, and the Keetmanshoop Rural in the south-east of Namibia. In the north and east there are dry forests covering an area of over 300,000 km² in which Rhodesian teak and several species of Acacia are prominent. These regions are termed Kalahari Acacia-Baikiaea woodlands AT0709. Outside the Kalahari "desert", but still in the Kalahari basin, a halophytic vegetation to the north is adapted to pans, lakes that are completely dry during the dry season, and maybe for years during droughts, such as in Etosha (Etosha Pan halophytics AT0902) and Makgadikgadi (Zambezian halophytics AT0908). A totally different vegetation is adapted to the perennial fresh water of the Okavango Delta, an ecoregion termed (Zambezian flooded grasslands AT0907).